gotosocial/internal/processing/fedi/user.go
kim 42d8011ff4
[chore/security] refactor AuthenticateFederatedRequest() to handle account deref + suspension checks (#2371)
* refactor AuthenticateFederatedRequest() to handle account suspension + fetching of owner

* small fixups

* small changes

* revert to 'IsEitherBlocked' instead of just 'IsBlocked" :grimace:

* update code comment to indicate that AuthenticateFederatedRequest() will handle account + instance dereferencing
2023-11-21 11:35:30 +01:00

122 lines
4.5 KiB
Go

// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package fedi
import (
"context"
"errors"
"fmt"
"net/url"
"github.com/superseriousbusiness/activity/streams/vocab"
"github.com/superseriousbusiness/gotosocial/internal/ap"
"github.com/superseriousbusiness/gotosocial/internal/db"
"github.com/superseriousbusiness/gotosocial/internal/gtserror"
"github.com/superseriousbusiness/gotosocial/internal/uris"
)
// UserGet handles the getting of a fedi/activitypub representation of a user/account,
// performing authentication before returning a JSON serializable interface to the caller.
func (p *Processor) UserGet(ctx context.Context, requestedUsername string, requestURL *url.URL) (interface{}, gtserror.WithCode) {
// (Try to) get the requested local account from the db.
receiver, err := p.state.DB.GetAccountByUsernameDomain(ctx, requestedUsername, "")
if err != nil {
if errors.Is(err, db.ErrNoEntries) {
// Account just not found w/ this username.
err := fmt.Errorf("account with username %s not found in the db", requestedUsername)
return nil, gtserror.NewErrorNotFound(err)
}
// Real db error.
err := fmt.Errorf("db error getting account with username %s: %w", requestedUsername, err)
return nil, gtserror.NewErrorInternalError(err)
}
if uris.IsPublicKeyPath(requestURL) {
// If request is on a public key path, we don't need to
// authenticate this request. However, we'll only serve
// the bare minimum user profile needed for the pubkey.
//
// TODO: https://github.com/superseriousbusiness/gotosocial/issues/1186
minimalPerson, err := p.converter.AccountToASMinimal(ctx, receiver)
if err != nil {
err := gtserror.Newf("error converting to minimal account: %w", err)
return nil, gtserror.NewErrorInternalError(err)
}
// Return early with bare minimum data.
return data(minimalPerson)
}
// If the request is not on a public key path, we want to
// try to authenticate it before we serve any data, so that
// we can serve a more complete profile.
pubKeyAuth, errWithCode := p.federator.AuthenticateFederatedRequest(ctx, requestedUsername)
if errWithCode != nil {
return nil, errWithCode // likely 401
}
// Auth passed, generate the proper AP representation.
person, err := p.converter.AccountToAS(ctx, receiver)
if err != nil {
err := gtserror.Newf("error converting account: %w", err)
return nil, gtserror.NewErrorInternalError(err)
}
if pubKeyAuth.Handshaking {
// If we are currently handshaking with the remote account
// making the request, then don't be coy: just serve the AP
// representation of the target account.
//
// This handshake check ensures that we don't get stuck in
// a loop with another GtS instance, where each instance is
// trying repeatedly to dereference the other account that's
// making the request before it will reveal its own account.
//
// Instead, we end up in an 'I'll show you mine if you show me
// yours' situation, where we sort of agree to reveal each
// other's profiles at the same time.
return data(person)
}
// Get requester from auth.
requester := pubKeyAuth.Owner
// Check that block does not exist between receiver and requester.
blocked, err := p.state.DB.IsBlocked(ctx, receiver.ID, requester.ID)
if err != nil {
err := gtserror.Newf("error checking block: %w", err)
return nil, gtserror.NewErrorInternalError(err)
} else if blocked {
const text = "block exists between accounts"
return nil, gtserror.NewErrorForbidden(errors.New(text))
}
return data(person)
}
func data(requestedPerson vocab.ActivityStreamsPerson) (interface{}, gtserror.WithCode) {
data, err := ap.Serialize(requestedPerson)
if err != nil {
err := gtserror.Newf("error serializing person: %w", err)
return nil, gtserror.NewErrorInternalError(err)
}
return data, nil
}